Combine melted butter, brown sugar & sugar.
Add eggs and vanilla
Add remaining dry ingredients and stir until just incorporated
Pour into greased 10x14 baking dish or divide between two 9x9 greased pans.
Sprinkle chocolate chips over cookie mixture
Make fudge brownies according to box instructions
Pour fudge batter evenly over cookie batter. Use spoon to swirl or spread if desired.
Bake at 325 for 28-34 minutes for a 10x14 pan or 22-24 minutes for 9x9 pan. or until middle is just set. You want to take these out just before they are done for maximum gooeyness.